Do you remember the time when... How episodes shape our memories by Jai Yu!

Imagine sitting with your friends chatting about previous trips. You might mention the time when you went to a beautiful waterfall. You mention some details of the event, like the sun, weather and scenery. You can remember the activities from that day. But would you remember the exact duration you were at the waterfall, apart from a crude number? Or what you did the day earlier or the day later. Probably not so clearly. The event became fresh in your memory, but many details were lost to time. How does the brain retain this experience.

Jai and colleagues investigated the phenomena of coding experiences in the brain to understand how the mind recollects past experiences. They used an interesting model where a rat's behavior is monitored while it searches for a reward and then consumes it. The rat's activity gets divided into mobility (searching for reward) and immobility (consumption of reward). The rat's brain uses the changes in activity as switches to break time into discrete chunks. Each chunk becomes an episode and might be processed and saved differently. This way the brain could define interesting parts of experience and save them as separate memories, such as memories of experience on paths to reach rewards versus memories of being at those reward locations. To know more on how this happens, please listen to Jai.



To know more, please refer to:
Distinct hippocampal-cortical memory representations for experiences associated with movement versus immobility
eLife, Aug., 2017

The sugar deception! Interview with Maria Veldhuizen to know if our brain can tricked into uncoupling sweetness from calorie content.

We all know of diet drinks and sugar-free desserts. Such foods have ingredients that are sweet, but low in calorie. The temptation to savor and relish sweet foods without paying the price of high calorie intake is pretty tempting, isn't it? But does taking food items with a mismatch in sweetness and calorie content actually work on our brains? Can our brain detect the disparity?

Maria and colleagues wanted to understand the affect of discrepancy between the sweetness of the food and its calorie content on the brain's response and metabolism. By providing people drinks that were of the same nutritional value, but varying in calorie, they found that the body responded the best when the two things, sweetness and calories, matched. This suggested that calories are not the only factor that trigger metabolic and mental responses. It could be that the brain's reward circuits better register foods that match in their sweetness and nutritional content. This is of great importance because we live in a world where increasing amounts of food contain such mismatches. To know more, please listen to Maria.


To know more, please refer to:
Integration of Sweet Taste and Metabolism Determines Carbohydrate Reward
Maria et al., Current Biology, 2017